Linux FAQ - Section 3
Compatibility with other operating systems

Question 3.1. Can Linux share my disk with DOS ? OS/2 ? 386BSD ? Win95 ?

Yes. Linux uses the standard PC partitioning scheme, so it can share your disk with other operating systems. Note, however, that many of these other operating systems are rather cranky: DOS FDISK and FORMAT can sometimes overwrite data in a Linux partition because they sometimes incorrectly use partition data from the partition's boot sector rather than the partition table. In order to prevent them from doing this it is a good idea to zero out under Linux the start of a partition you've just created, before you use MSDOS or whatever to format it. Type: 
   dd if=/dev/zero of=/dev/hdXY bs=512 count=1
where hdXY is the relevant partition, eg, hda1 for the first partition of the first (IDE) disk.

Linux can read and write the files on your DOS and OS/2 FAT partitions and floppies using either the DOS filesystem type built into the kernel or mtools. There is an alpha version of kernel support for the VFAT filesystem used by Windows 95 and Windows NT; it is available from mm-ftp.cs.berkeley.edu in /pub/multimedia/linux/vfat/vfat-0.3.0.tgz. This was integrated into the standard kernel in version 1.3.60.

See Q1.2 `What software does it support ?' for details and status of the emulators for DOS, MS Windows and System V programs.

See also Q3.5 `Can I access BSD FFS, SysV UFS, Mac, Amiga, etc filesystems ?'.

Question 3.2. How do I access files on my DOS partition or floppy ?

Use the DOS filesystem, i.e. type, for example: 
        mkdir /dos
        mount -t msdos -o conv=text,umask=022,uid=100,gid=100 /dev/hda3 /dos
If it's a floppy, don't forget to umount it before ejecting it !

You can use the conv=text/binary/auto, umask=nnn, uid=nnn and gid=nnn options to control the automatic line-ending conversion, permissions and ownerships of the files in the DOS filesystem as they appear under Linux. If you mount your DOS filesystem by putting it in your /etc/fstab you can record the options (comma-separated) there, instead of defaults.

Alternatively you can use `mtools', available in both binary and source form on the FTP sites -- see Q2.5 `Where can I get Linux material by FTP ?'.

A kernel patch (known as the fd-patches) is available which allows floppies with nonstandard numbers of tracks and/or sectors to be used; this patch is included in the 1.1 alpha testing kernel series.

Question 3.3. Can I use my Stacked/DBLSPC/etc. DOS drive ?

Not very easily. You can access them from within the DOS emulator [Q1.2 `What software does it support ?'], but it's harder to do as a normal filesystem under Linux or using mtools. There is a module available for the Linux kernel which can do read-only access of the compressed volume. Look on sunsite.unc.edu in /pub/Linux/system/Filesystems, for the ths package.

Question 3.4. Can I access OS/2 HPFS partitions from Linux ?

Yes, but it's only read-only at the moment. To use it you must compile a kernel with support for it enabled [Q7.6 `How do I upgrade/recompile my kernel ?']. Then you can mount it using the mount command, for example: 
        mkdir /hpfs
        mount -t hpfs /dev/hda5 /hpfs

Question 3.5. Can I access BSD FFS, SysV UFS, Mac, Amiga, etc filesystems ?

I'm told that there is a primitive, alpha test read-only Amiga filesystem on sunsite.unc.edu in /pub/Linux/patches/amigaffs.tar.Z. More information is in affs-readme in the tarfile.

Recent kernels contain support for the UFS filesystem used by System V, Coherent and Xenix.

There is alpha kernel support, readonly for the moment, for the 4.2BSD UFS, on sunsite.unc.edu in /pub/Linux/ALPHA/ufs.

There is a set of user-level programs that provides read-only access to the Macintosh hierarchical filing system (HFS). It is available on sunsite.unc.edu in /pub/Linux/utils/disk-management/hfs0_36.tgz. This is being turned into a kernel module, which is available on sunsite.

A suite of programs called Samba provide support for Windows for Workgroups networked filesystems (provided it's configured to use TCP/IP). Information is available at http://lake.canberra.edu.au/samba/samba.html. There is alpha kernel support for mounting such filesystems, on sunsite.unc.edu in /pub/Linux/ALPHA/smbfs.

There is no support for the rest of those yet; I have not heard of any recent work on providing some.

Question 3.6. Can I run Microsoft Windows programs under Linux ?

Not yet. There is a project, known as WINE, to build an MS Windows emulator for Linux, but it is not ready for users yet. Don't ask about it unless you think you can contribute; look out for the status reports in comp.emulators.ms-windows.wine.

In the meantime if you need to run MS Windows programs your best bet is probably to reboot when you want to switch environments. LILO (the Linux bootloader) has the facility for a boot menu --- see its documentation for more details.

Question 3.7. How can I boot Linux from OS/2's Boot Manager ?

1. Create a partition using OS/2's FDISK (Not Linux's fdisk).

2. Format the partition under OS/2, either with FAT or HPFS. This is so that OS/2 knows about the partition being formatted. (This step is not necessary with OS/2 "warp" 3.0.)

3. Add the partition to the Boot Manager.

4. Boot Linux, and create a filesystem on the partition using mkfs -t ext2 or mke2fs. At this point you may, if you like, use Linux's fdisk to change the partition type code of the new partition to type 83 (Linux Native) -- this may help some automated installation scripts find the right partition to use.

5. Install Linux on the partition.

6. Install LILO on the Linux partition -- NOT on the master boot record of the hard drive. This installs LILO as a second-stage boot loader on the Linux partition itself, to start up the kernel specified in the LILO config file. To do this you should put 

   boot = /dev/hda2
(where /dev/hda2 is the partition you want to boot off) in your /etc/lilo/config or /etc/lilo.config file.

7. Make sure that it is the Boot Manager partition that is marked active, so that you can use Boot Manager to choose what to boot.

Question 3.8. How can I share a swap partition between Linux and MS Windows ?

See the Mini-HOWTO on the subject by H. Peter Anvin, hpa@yggdrasil.com. It is available on sunsite.unc.edu in /pub/Linux/docs/HOWTO/mini/Swap-Space.
Next: Linux's handling of filesystems, disks and drives.
Back: Network sources and resources.
Return to contents.

Ian Jackson / ijackson@gnu.ai.mit.edu - 06 March 1996

Extracted from Linux Frequently Asked Questions with Answers, Copyright Ian Jackson 1996.